Presser-foot mechanism for sewing machines



April 29, 1930. F. ASHWORTH PRESSER FOOT MECHANISM FOR SEWINGMACHINES Original Filed April'l9, 1919 I m/entar 7MW 2 i Fig 2 mtness Patented Apr. 29, 1930 FRED ASHWORTI-I, OF BEVERLY, IvIASSACHUSETTS, ASSIGNOR TO UNITED SHOE MA- CHINERY CORPORATION, OF PATEBSON, NEW JERSEY, A CORPORATION OF JERSEY PRESSER-FOOT MECHANISIH FOB SERVING MACHINES Application filed April 19, 1919, Serial No. 291,267. Renewed July 13, 1923.

This mechanism relates to sewing machines and more particularly to presser foot mechanisms for such machines.

The invention constitutes an improvement in presser foot mechanisms of the type in which the presser foot is locked in workclamping condition during the stitch formation to hold the work securely, and is unlocked when the feed movement of, the work takes place to allow the work to be fed forward between the work support and presser foot. The invention is particularly designed to be applied to machines of the class employed in sewing outsoles to the welts of welted shoes and is illustrated in this. application as embodied in a machine of this class, but it is also applicable to other machines.

One object of the present invention is to produce an improved presser foot mechanism of this type which is simple in construction and reliable in operation, which is not subject to undue wear, and which will operate in an efficient manner when the parts be come worn by long continued use.

Another object of the invention is to produce a novel and improved presser foot mechanism which may be readily applied to certain machines for sewing outsoles now in common commercial use.

With these objects in view, the invention consists in certain novel and improved constructions, arrangements and combinations of parts hereinafter described and particularly pointed out in the claims the advantages of which will be understood and ap preciated by those skilled in the art.

The features of the invention will be readily understood from the accompanying drawings illustrating a machine embodying the invention in its preferred form and'the following detailed description of the constructions therein shown.

'In the drawings Figurel is a View in side elevation of a portion of an outsole sewing machine embodying the invention illustrating particularly'the presser foot mechanism; and Fig. 2 is a veiw in side elevation of a portion of themechanism shown in Fig. 1 illustrating the parts in difierent positions.

The outsole shoe sewing machine illustrated in the drawings is a machine of the'same general type as that illustrated'and described in applicants Patent, No. 1,169,909, dated d curved work feeding awl 4:, a work .supportfi,

andv a presser foot The presser foot 8 is of the usual construction and is secured to the forward end of the presser foot lever 10 which is pivoted on the stud In the present embodimentof the invention, the presser foot has the following mode of operation during each cycle of stitch. forming operations of the machine.

During the action of the stitch formingcdevices in forming a stitch the presser foot is locked in clamping engagement with the work so that the work is tightly clamped between the presser foot and the work support. During the feeding of the work, however, the presser foot is unlocked and then rests lightly on the work so as toofier practically no resistance to the feeding movement of the work. At the end of the feeding movement of the work, the presser foot is pressedinto engagement with the'workwith a comparatively heavy pressure so as to clamp the stock firmly against the work support, and

is then locked in position. The presser foot remains locked until the beginning of the feeding operation, when it is again unlocked, the cycle of operations being repeated.

The locking mechanism for the presser foot comprises a wedge block 14 pivotally supported on the lower end of a link 16 which is pivotally connected at its upperend with the rear end of. the presser foot lever 10. The lateral faces of the wedge block 14 are preferably arranged at a, relatively small acute angle to each other, as shown in the drawings. A contact, or guide plate 18, secured to the frame, is arranged to engage the rear face ofthe wedge block 14 and acts to limit the movement of the wedge block laterally in one direction. A longitudinally movable, locking wedge block 20 is arranged to engage the forward face of the wedge block. 14 to lock the same from downward movement. The locking Wedge block is confined between the wedge block 14 and a contact or guide plate 22 secured to the frame, the rear face ofwhich is inclined to a slight degree relatively to the forward face of the contact plate 18 So that these faces converge'downwardly, the locking wedge block being shaped to fit m in; the recess between the wedge block 14 and the rear face of the contact plate-22;

The lockin wedge block is pivotally supported on the lower end-of a link 24, the

upper end of which is pivotally connected with the forward endof one arm of a lever 2,6 pivoted on a stud-28. The lever 26 is acted upon by a spring 30 connected with "another arm thereof which tends to swing the-lever in ardirection to elevate the locking wedge block 20'. When the locking wedge block is held; by the action of the spring 30 in its upper position in engagement with the Wedge block 14 and with the contact plate 22, the wedge block 14 isclamped with considerablepressure between the lockingv wedge block and the contact plate 18. The force exerted by the spring 3O on the locking wedge block 20, tendingto move the locking wedge block upwardly has a resultant greater than said forcefwhich tends to move the wedge block '14 upwardly, and the presser foot lever 10 is thus acted upon to force the presser foot against the work with a heavy pressure to clamp the work. WVhen the locking wedge block is in looking position any tendencv to lift the presser foot, and thereby to move the wedge block 14 downwardly, will greatly increase the pressure of the rear face of said wedge block againstthe forward face of the plate 18, the pressure of the forward face of said wedge block against the rear face of the locking wedge block 20 and the pressure of the locking wedge block against the rear face of the contact plate 22. The frictional action of these contacting faces resists any tendency to downward movement of the wedge block 14. The area of contact of these faces in the present construction is considerable and the frictional resistanceexerted thereby'is sufficient effectively to counteract any tendency to overcome the resultant force of the spring 30. The locking wedge block, therefore, will hold the presser foot locked securely in clamping engagement with the work.

The lockingwedge block is held by the coiled spring 30 in locking position during the. reater part of each cycle of operationsof the machine. Just before the work is fed, however, the locking wedge block is depressed against the action of said coiled spring, as shown in Fig. 1. The depression of the locking wedge block releases the samefrom forcible engagement with the wedge block 14, so that the latter wedge block is then free to move downwardly and the presser foot' is relieved from clamping engagement with the work. The presser foot maybe lifted from the work as t-he'locking wedge block is depressed, or the presser foot may then be held lightly in engagement with the work by the action of a relatively light spring so that it offers practically no resistance to the feeding of the work between the presser foot and work support. \Vhen the feeding of the work-has been completed the locking wedge block 20 is again moved upwardly by the action of i,

the coiled spring 30 thereby through it-s action on the Wedge block 14, forcing the pres'ser foot firmly into engagement with the work and locking the same' in position.

The mechanism for thus actuating and controlling the locking wed e block" comprises a rod 34 pivotally connected at itslower end by a pin 86 with another arm. on the lever 26. Upon the upperend of the rod 34 is slid-ably mounted a sleeve 38 ina slot in which is pivoted at 40 a grippingarm or lever 42 having an eccentric face arranged to engage a flat'snrfa'ce formed on the rod to grip the. rod. The forward endof. the

gripping lever 42 is pivotallyconnected with the forwardlyextending arm of a cam lever 44 pivoted on a stud46, the rearwardly extending arm of which'carries a cam roll 48 engaging in a cam' groove in a cam disk-50 mounted on the main shaft '52 of the machine.

The sleeve 38 is acted upon by a coiled spring,

54 surrounding the rod 34 and interposed between the sleeve and a clampblock 55 clamped adjustably on the rod by means of a clamping screw which tends-to move the -sleeve upwardly relatively to the rod. The l upward movement of the sleeve is limited by means of a stop arm 57 formed on the to en a e the upper end of the sleeve as wedge block 20 is then held in its upper lim iting or locking position by the action of the coiled spring 80, the strength of the coiled sprlng 54 wh ch then tends to move the rod. 84

downwardly, and to swing the lever 26 in a '7 direction to depress the locking wedge block.

being very slight as compared with that of the spring 30. When the forward armof the cam lever 44 1s swung downwardly the gripping lever 42 is first swung downwardly about its pivotal connection with the sleeve 38 until the eccentric portion of the gripping -to depress the locking wedge block. As the forward arm of the cam lever 44rswings upwardly, the eccentric portion of the gripping lever 42 is held in gripping engagement with the rod 34 until the upper end of the sleeve 38 engages the stop arm 57, after which the gripping lever swings upwardly about its pivotal connection with the sleeve thereby releasing the eccentric portion of the gripping lever from engagement with the rod 34. The release of the rod allows the locking wedge block to be forced upwardly by the action of the spring to force the presser foot firmly into engagement with the work and to lock the same in position. With this mechanism for actuating and controlling the locking wedge block, the wedge block is moved a relatively slight uniform distance during each cycle of the machine to unlock the presser foot, regardless of the locking position :1 of the locking wedge block which varies with variations in the position of the presser foot due to changes in the thickness ofthe work.

To enable the presser foot to be lifted dur-' ing each cycle of operations, if desired, a pin 58'is mounted in the wedge block 14 and is arranged to project therefrom beneath the clamp block 55. When it is desired to allow 7 the presser foot to remain in engagement with the work as the locking wedge block 20 is depressed to unlock the presser foot, the clamp block is adjusted on the rod 34 so that it will not engage the pin 58 during the downward movement of the rod. The presser foot is then held lightly in engagement with the work by means of a coiled spring 59 connected at its upper end with the arm 57 and at its lower end with the rear end of the presser foot lever 10. When it is desired to lift the presser foot during each cycle of operations of the machine, the clamp block 55 is adjusted on the rod 34 so that it will engage the pin 58 during the downward movement of the rod 34 just after the locking wedge block 20 is depressed sufficiently to unlock the presser foot. The presser foot is then lifted by the downward movement imparted to the wedge block 14 by the clamp block 55, as shown in Fig. 1, as the rod 34 continues its downward movement. lVit-h this adjustment of the block the presser foot will belifted a substantially uniform distance from the work during each cycle of operations.

. The machine illustrated is provided with a pull-off mechanism comprising thread guiding eyes 60 and 61 formedon an arm 62 secured to a rock shaft es, and a pull-off arm 66 arranged to operate between the thread guiding eyes, this mechanism having the same construction and mode of operation as the pull-ofi' mechanism illustrated and described in applicants patent referred to above. In order to varythe position of the thread-'guict ing eyes 60 and 61 with relation tothe pulloff arm 66, so that the pull-01f arm will operate to pull Of[ the required quantityof thread during each cycle of operations in accordance with the thickness of the work, a second arm 68 is secured to the rock shaft 64 and is connected by a link 70 with the arm of the lever 26, which supports the locking wedge block.

The 1 present machine is provided with mechanism for depressing the locking wedge block to unlock the presser foot and for actu- 'ating the presser foot lever to lift the presser foot when the presser foot is normallylocked in work engaging position to permit the removal, insertion or adjustment 'of the work. This mechanism is constructed and arranged to be-actuated automatically to unlock and lift the presser foot upon stopping the ma chine and also is adapted to be actuated manually. In the construction illustrated this mechanism comprises a lever 72 pivotally mounted on the stud l2, and a link 74 pivotal-.

ly connected at its upper end with a rearwardly eXtending .arm on the lever 72, and having its lower end formed with a, slot 7 6 in which engages the pin 36 which connects the rod 34 with the: lever 26. The lever 72 is provided with an upwardly extending arm which is connected by a. link or bar 78 with aleverpivoted at the rear of. the main shaft 52, and adapted to be actuated from a cam carried by the shaft upon stopping the machine. the link 78 is connected and. the mechanism The lever with whichthe rearend of for actuating the lever upon stopping the machine are fully illustrated and described in applicants Patent, No. 1,233,539, dated July 17,1917. The mechanism illustrated in said patent operates to swing the lever to which the rear end of the link 78 is connected rearwardly upon stopping the machine, and the link will thereby be moved'longitudinally to the rear, and the lever 72 will be swung about the stud 12 in a direction to depress the link 74. During the swinging movement thus imparted to the lever 7 2 the upper end of the slot 7 6 in' the link engages the pin 36 and the lever 26 is thereby actuated to depress the locking wedge block 20. The downward movement of the link also depresses the rod 34 and as the rod moves downwardly the clamp block 55 engages the pin 58 and the presser foot lever is actuated to lift the presser foot. The lever 72 may be actuated manually to unlock and lift the presser foot by grasping the upwardly extending arm of the lever and swinging the same rearwardly. Theslot 7 6 in the link 7 4 allows the pin 36 to move independently of the link during the operation of the presser foot mechanism in each cycle of. operations of the machine.

Having explained the nature and object of the invention and having specifically described a machine embodying thesame in its preferred form, what is claimedis:

1'. A sewing machine having, in combination, stitch forming devices, a work support,

a'presser foo,t, a presser foot carrier, a Wedge block and connections betweenthe same and the pull-off for varying the thread drawing oif action of the pull-off.

2. A sewing machine having, in combination, stitch forming devices, a-work'support, a presser foot, a presser. foot lever, a link pivotally connected-with the rear end of the presser foot lever, a wedgepblockpivotally supported on the link, a locking-wedge block supporting lever, a link pivotally connected V a pressertoot, two relatively movable coopwedge with the supportingleveiy, a locking block pivotally supported on the heir, guides for the respective wedge blocks, and means for actuating said supporting lever to move the locking wedge block into andoutot locking position during each cycle of operations.

3. Asewing machine having, in combination, stitch forming devices, a work support, a presser foot, a presser'foot carrier,a wedge block and connections between'the same and the presser foot carrier, a locking wedge block arranged to engage the first wedge block on a plane inclined to the directions of movement of both wedge blocks,a lever on which the locking wedge block is supported, a spring acting on the lever and tending to swing the same in a direction to move the lockmeans for swinging the lever a substantially uniform distance during each cycle of operations to move the locking wedge block out of locking position. p j Y 4. A sewing machine having, in combination, stitch forming devices, a work support,

a presser foot, a presser foot carrier, a wedge block and connections between the same and the presser footcarrier. a locking wedge block supporting lever, a locking wedge block supported on the lever, means for actuating the lever to move the locking wedge blocl: into and out of locking position during each cycle of operations, pull-oil mechanism comprising an arm, thread eyes carried by saic arm, a thread engaging'pull-off armoperating between said thread eyes, a rock shaft-to which the first arm issecured, a second arm secured to said rock shaft, and a link connecting the locking wedge block supporting leve with ,the lastarm. r

5. A sewing machine having, in combination, stitch forming devices, a work support, a presser foot; tXVOlBlEIlTlVQlY- movable cooperatin wed e blocks arran ed to contact with D D D 7 each other on a plane inclined to the directions of movement of both wedge blocksfor locking the presser foot, and means ior relatively actuating said wedge blocks to lock and unlock the presser foot andfor lifting the'presser "foot when the presser foot is unlocked during each cycle or" operations;

6. A sewing machine havingin combination, stitch fern ing devices, a work support,

a presser foot, a presser foot carrier, awedgc block and connections between the same andthe presser foot carrier for moving said wedge is 7 block with the carrier,a locking, wedge block torengaging the first wedge block on a plane inclined to the directions ct movement of both wedge blocks, and means for moving the locking wedge block to lock and unlock the carrier and tor moving the carrier to lift the ing each cycle or operations. 7

A sewing machine having, in comb-ina tion, stitch forming devices, a work support,

crating wedge blocks arranged to contact with each other one plane inclined to the directions of movement of both wedge blocks and acting to lock and unlock the'fpresser foot during each'cycle of operations, and means for relatively moving the wedge blocks to unlock the presser foot and forlifting the pressroot when the presser toot is-normally 1 locked in work engaging position.

moving the locking wedge block to lock and i unlock the carrier and for lifting the presser foot" comprising a longitudinally movable roo, a connection between therod and the locking wedge block, a block secured to the rod, and a pin mounted on'the first wedge block andrarranged to be engaged by the block during the unlocking movement of the rod to actuate the first wedge block to lift the presser foot. I i

A sewing machine having, in combinatien, stitch forming devices, a work support,

presser foot, two relative y movable cooperating wedge blocks, means for relatively actuating the wedge blocks to lock and unlock 11161113 with the work as the wedge blocks are relatively actuated to unlock the presser foot.

FRED ASHVVORTH.

' presser foot when the carrier is unlocked dur- 

